This political science-y piece shows pretty clearly what most political observers outside the Beltway-Mustache-Axis-of-Bipartisan-Fetishism intuitively understand: there simply isn’t a constituency for “centrist” efforts like Americans Elect:

Both Democrats and Republicans are now closer to their own party and farther from the opposition party than at any time in the past four decades. Democrats on average place the Democratic Party exactly where they place themselves while they place the Republican Party very far to the right of where they place themselves. And Republicans on average place the Republican Party exactly where they place themselves while they place the Democratic Party very far to the left of where they place themselves. As a result, very few supporters of either party are likely to be tempted to vote for a centrist third party.

There is one group of voters that might be tempted to vote for a centrist third party: pure independents. These voters, on average, place themselves right in the middle of the two major parties and rather far from either one. But pure independents typically make up less than 10% of the electorate, and they tend to be less interested in politics and less attentive to political campaigns than voters who identify with a political party. There are simply not enough of them and they are too hard to mobilize to have a major impact on the outcome of a presidential election.

One caveat: Sabato’s charts measure perception of where the parties stand ideologically, not where they actually stand, and I’d question how much of a drift leftward there’s actually been on the Democratic side. The influence of the DLC and its fellow travellers has obviously waned, and the Blue Dogs took a kick to the gut in 2010, but that just means that the Dems are less ideologically diverse – not that, say, the Overton Window of permissible range of discussion has actually moved leftward within the party. Dennis Kucinich is as much of an outlier now as he was 10 years ago. The same cannot be said for Jim DeMint.

That said, Sabato’s piece shows the inherent irrelevance of efforts like Americans Elect, which posit a groundswell of support from voters that simply don’t exist. The people channelling David Broder from beyond the grave, who wax nostalgic for the days when pols drank at the same clubs and cut cordial backroom deals, are also pining for a political system in which voters’ wishes were routinely ignored. Those voters are, in 2012, living in two different worlds. They both hate Congress not because it’s gridlocked, but because it isn’t doing their bidding. And in the freakishly unlikely event a third-party presidential bid would be successful, it would still leave us with a Congress that was, if anything, even more gridlocked, for the simple reason that our political system isn’t designed to handle two extremely polarized political camps.

Wishing for a political system that ignores that inconvenient fact is wishing for a top-down, anti-democratic political system that represents almost nobody – the very antithesis of the “nominate whoever you want!” approach Americans Elect claims to embrace. The people backing such appeals to centrism would be better off using their considerable media platforms to explore how our country’s citizens could become less polarized, rather than pretending the polarization doesn’t exist.